Completely Geometrically Optimized DFT/ONIOM Triple-Helical Collagen-like Structures Containing the ProProGly,ProProAla,ProPro~DAla,and ProPro~DSer Triads

摘要

The structural protein,collagen,recently reviewed,consists of triple helical peptides whose structure was proposed by Rich and Crick,in which each of three peptide strands contains the repeating amino acid triad XaaYaaGly,where Xaa and Yaa can be any amino acid residues.In this structure,each peptide strand H-bonds to one of the other two using its Gly N-H's as donors,and to the third,using C=O's on other amino acid residues as acceptors.These triple helices are rich in proline and 4-(R)-hydroxyproline(Hyp),which constitute about 20% of the amino acid content,while the most common repeating unit is Pro-Hyp-Gly.Various diseases,such as osteogenesis imperfecta,Ehlers-Danlos syndrome,Alport syndrome,Schmid metaphyseal chondrodysplasia,and dystrophic epidermolysis bullosa,result from amino acid residue mutations in collagens,mostly mutations of Gly.